Daesh-affiliated Boko Haram is leading a nine-year long insurgency against the governments of Nigeria, Niger, Cameroon and Chad. The ongoing humanitarian crisis has resulted in more than 20,000 deaths and displaced 2.4 million people.

21 Chibok girls are united with their families after being released from Boko Haram in October 2016. The Red Cross and the Swiss government negotiated their return. Three years after the Chibok abduction, more than 200 girls are still being held.

In 2002, Mohammad Yusuf, a young charismatic preacher creates Jama't Ahl as-Sunnah lid-Da'wah wal-Jihad, in Borno State in north-east Nigeria. The group is more commonly known by its moniker Boko Haram, meaning "Western education is sin."

In 2009, after falling out with then Borno State governor Kashim Shettima, he is arrested and killed in police custody along, with 900 of his followers.

After the Nigerian government's crackdown on Boko Haram, Abubakar Shekau, one of Mohammed Yusuf students, takes control of the group that has radicalised into underground militant cells.

Under Shekau's leadership, Boko Haram conducts its first suicide bombings against churches and mosques in northern Nigeria.

As Goodluck Jonathan ascends to the presidency in 2010, the group continues to target security personnel. In 2012, Jonathan declares a state of emergency in three north-eastern states.

According to Human Rights Watch, by December 2013, 130 villages have been attacked and are controlled by the group.

According to the United Nations, Boko Haram-related violence caused more than 7,831 deaths in 2014 alone, internally displaced almost one million people, and created 130,000 Nigerian refugees in Cameroon, Niger and Chad.

The group swears allegiance to Daesh in March 2015 and changes its name to Islamic State of West Africa Province (ISWAP).

Nigeria's newly elected President Muhammadu Buhari reshuffles the military leadership and sets December 2015 as the deadline to defeat Boko Haram.

Boko Haram rapidly loses control of territory and the Nigerian government states that it has severely weakened the group, claiming that its fighters are hiding in the Sambisa forest.

In August 2016, Daesh announces that it has appointed Abu Musab al Barnawi, the son of founder Mohammad Yusuf, as the new leader of Boko Haram.

Shekau challenges the appointment, leading to a split into pro-Barnawi and pro-Shekau supporters.

According to the UN, the Lake Chad basin crisis is worsening as 10.7 million are in need of humanitarian assistance in Niger, Chad, Cameroon and Nigeria. 2.4 million people are displaced, including 1.4 million children. Meanwhile, 7.1 million are suffering from acute food insecurity.